Treatment of tumors using specific anti-L1 antibody

ABSTRACT

The present invention relates to the anti-L1 monoclonal antibody 9.3 as well as to related antibodies or binding molecules and well as to the uses thereof, especially in tumor treatment.

This application claims benefit of U.S. provisional application Ser. No. 60/944,359 filed Jun. 15, 2007, which is incorporated herein by reference in its entirety.

The present invention relates to the treatment of tumors by the use of a specific anti-L1 antibody.

The standard treatment of advanced cancer is often chemotherapy or radiotherapy. However, despite initial response to therapy, it is often observed that different carcinomas acquire resistance to chemotherapeutic drugs or radiotherapy leading to tumor recurrence and frequent death of the patients. Often, it is then decided to switch to another chemotherapeutic drug or to higher dosages. However, often no improvement of the clinical situation is observed.

L1 is a type I membrane glycoprotein of 200 to 230 kDa structurally belonging to the Ig superfamily (Moos M, Tacke R, Scherer H, Teplow D, Fruh K, Schachner M. Neural adhesion molecule L1 as a member of the immunoglobulin superfamily with binding domains similar to fibronectin. Nature 1988; 334:701-3). L1 plays a crucial role in axon guidance and cell migration in developing nervous system (Hortsch M. Structural and functional evolution of the L1 family: are four adhesion molecules better than one? Mol Cell Neurosci 2000; 15:1-10, Schachner M. Neural recognition molecules and synaptic plasticity. Curr Opin Cell Biol 1997; 9:627-34). Recent studies have also implicated L1 expression in the progression of human carcinomas. L1 expression was found on different tumors including lung cancer (Katayama M, Iwamatsu A, Masutani H, Furuke K, Takeda K, Wada H, et al. Expression of neural cell adhesion molecule L1 in human lung cancer cell lines. Cell Struct Funct 1997; 22:511-6), gliomas (Senner V, Kismann E, Puttmann S, Hoess N, Baur I, Paulus W. L1 expressed by glioma cells promotes adhesion but not migration. Glia 2002; 38:146-54), melanomas (Thies A, Schachner M, Moll I, Berger J, Schulze H J, Brunner G, et al. Overexpression of the cell adhesion molecule L1 is associated with metastasis in cutaneous malignant melanoma. Eur J Cancer 2002; 38:1708-1, Fogel M, Mechtersheimer S, Huszar M, Smimov A, Abu D A, Tilgen W, et al. L1 adhesion

molecule (CD 171) in development and progression of human malignant melanoma Cancer Lett 2003; 189:237-47), renal carcinoma (Meli M L, Carrel F, Waibel R, Amstutz H, Crompton N, Jaussi R, Moch H, Schubiger P A, Novak-Hofer I. Anti-neuroblastoma antibody chCE7 binds to an isoform of L1-CAM present in renal carcinoma cells. Int J Cancer, 1999; 83; 401-408, Allory Y, Matsuoka Y, Bazille C, Christensen El, Ronco P, Debiec H. The L1 cell adhesion molecule is induced in renal cancer cells and correlates with metastasis in clear cell carcinomas. Clin Cancer Res 2005; 11:1190-7) and colon carcinoma (Gavert N, Conacci-Sorrell M, Gast D, Schneider A, Altevogt P, Brabletz T, et al. L1, a novel target of beta-catenin signaling, transforms cells and is expressed at the invasive front of colon cancers. J Cell Biol 2005; 168:633-42). Furthermore, it is known in the art that L1 is overexpressed in ovarian and endometrial carcinomas in a stage-dependent manner (Fogel M, Gutwein P, Mechtersheimer S, Riedle S, Stoeck A, Smirnov A, et al. L1 expression as a predictor of progression and survival in patients with uterine and ovarian carcinomas. Lancet 2003; 362:869-75).

In the art, it has been suggested to use anti-L1 antibodies for the treatment of ovarian and endometrial tumors (cf. WO 02/04952, WO 06/013051 and Arlt M J, Novak-Hofer I, Gast D, Gschwend V, Moldenhauer G, Grunberg J, et al. Efficient inhibition of intra-peritoneal tumor growth and dissemination of human ovarian carcinoma cells in nude mice by anti-L1-cell adhesion molecule monoclonal antibody treatment Cancer Res 2006; 66:93643). In the art various anti-L1 antibodies are known (e.g. mAb 14.10: Huszar M, Moldenhauer G, Gschwend V, Ben-Arie A, Altevogt P, Fogel M: Expression profile analysis in multiple human tumors identifies L1 (CD171) as a molecular marker for differential diagnosis and targeted therapy. Hum Pathol 37:1000-1008, 2006, mab chCE7: Meli M L, Carrel F, Waibel R, Amstutz H, Crompton N, Jaussi R, Moch H, Schubiger P A, Novak-Hofer I: Anti-neuroblastoma antibody chCE7 binds to an isoform of L1-CAM present in renal carcinoma cells. Int J Cancer 83:401-408, 1999, mAb UJ127.11: Patel K, Kiely F, Phimister E, Melino G, Rathjen F, Kemshead J T: The 200/220 kDa antigen recognized by monoclonal antibody (MAb) UJ127.11 on neural tissues and tumors is the human L1 adhesion molecule. Hybridoma 10:481-491, 1991, mAb 5G3: Wolff J M, Frank R, Mujoo K, Spiro R C, Reisfeld R A, Rathjen F G: A human brain glycoprotein related to the mouse cell adhesion molecule L1. J Biol Chem 263:11943-11947, 1988). Furthermore, in Sebens Müerkoster et al., Oncogene. 2007 Apr. 26; 26(19): 2759-68, Epub 2006 Nov. 6, it has been suggested to use anti-L1 antibodies for sensitizing tumor cells for the treatment with a chemotherapeutic drug or with radiotherapy.

There is always a need for improved anti-tumor agents.

The present invention relates in one aspect to an anti-L1 monoclonal antibody which is capable of binding to the same L1 epitope recognized by the monoclonal antibody 9.3, produced by the hybridoma cell deposited under DSMZ ACC2841.

In the context of the present invention, it has been surprisingly found that the monoclonal antibody 9.3, produced by the hybridoma cell deposited under DSMZ ACC2841, has improved anti-tumor capacities (see examples). Especially, the monoclonal antibody 9.3 has the best ability to inhibit tumor growth and invasion of tumor cells of all antibodies tested. Furthermore, the monoclonal antibody 9.3 seems to abolish chemoresistance to a greater extend than the antibody 11A tested in WO 2008/046529 (see example 13).

Monoclonal antibodies and the production of monoclonal antibodies belongs to the state of the art and is also described in the references cited in the Materials and Methods section of the examples. In general, monoclonal antibodies can, for example, be prepared in accordance with the known method of Winter & Milstein (Winter, G. & Milstein, C. (1991) Nature, 349, 293-299). An alternative to preparing monoclonal antibody-secreting hybridomas, a monoclonal antibody directed against a polypeptide of the invention can be identified and isolated by screening a recombinant combinatorial immunoglobulin library (e.g., an antibody phage display library) with the polypeptide of interest. Kits for generating and screening phage display libraries are commercially available (e.g., the Pharmacia Recombinant Phage Antibody System, Catalog No. 27-9400-01; and the Stratagene SurfZAP Phage Display Kit, Catalog No. 240612). Additionally, examples of methods and reagents particularly amenable for use in generating and screening antibody display library can be found in, for example, U.S. Pat. No. 5,223,409; WO 92/18619; WO 91/17271; WO 92/20791; WO 92/15679; WO 93/01288; WO 92/01047; WO 92/09690; WO 90/02809; Fuchs et al., 1991, Bio/Technology 9:1370-1372; Hay et al., 1992, Hum. Antibod. Hybridomas 3:81-85; Huse et al., 1989, Science 246:1275-1281; Griffiths et al., 1993, EMBO J. 12:725-734.

Since the effect of an antibody is mediated by its capacity to bind a specific epitope, the invention relates to all monoclonal antibodies recognizing the same epitope as the antibody 9.3. Methods for determining the epitope of a given antibody are known in the art and include the preparation of synthetic linear peptides of a given region of interest and the subsequent testing whether the antibody binds to said peptides (see Epitope Mapping, A practical approach, Oxford University Press 2001, Editors: Olwyn Westwood and Frank Hay). Alternatively, different recombinant proteins covering the region of interest can be produced and tested for the binding of the antibody (Oleszewski, M., Gutwein, P., von der Lieth W., Rauch, U., Altevogt, P. Characterization of the L1-neurocan binding site. Implications for L1-L1 homophilic binding. J. Biol. Chem. 275: 34478-34485 (2000).

Furthermore, once a specific epitope of a monoclonal antibody is known, it is within the skill of the person skilled in the art to identify or prepare other antibodies, especially monoclonal antibodies, or binding molecules as defined below which bind to the same epitope. For example, it is possible to use the peptides or proteins described above in the context of the epitope mapping also for the identification or production of said antibodies or binding molecules.

As it can be taken from the examples, the epitope of the antibody 9.3 is with the first immunoglobulin-like domain of L1. Therefore also the epitope of the monoclonal antibody of the invention is preferably within the first immunoglobulin-like domain of L1.

In another aspect, the invention relates to an anti-L1 monoclonal antibody, having the same capacity to inhibit tumor growth as the monoclonal antibody 9.3, produced by the hybridoma cell deposited under DSMZ ACC2841. This capacity can be tested by using the same tumor growth assay as described in the Example 1, section 1.3.9. According to the invention, “the same capacity” means that the monoclonal antibody has a tumor growth inhibiting capacity which does not differ more than 5% from the tumor growth inhibiting capacity of the monoclonal antibody 9.3.

Preferably, this antibody of the invention also inhibits L1 dimerization, as it has been shown for the antibody 5G3 (see above).

In another aspect, the invention relates to an anti-L1 monoclonal antibody, characterized in that at least one of its complementarity determining regions (CDRs)

-   -   a) has one of the following sequences RASQDISNYLN (SEQ ID NO:         1), YTSRLHS (SEQ ID NO: 2), QQGNTLPWT (SEQ ID NO: 3), RYWML fSEQ         ID NO: 4), EINPRNDRTNYNEKFKT (SEQ ID NO: 5), or GGGYAMDY (SEQ ID         NO: 6) or     -   b) has a sequence which, in comparison to the sequences         mentioned under a) has at least one conservative amino acid         exchange.

The above mentioned sequences show the CDRs of the monoclonal antibody 9.3 determined according to the method of Kabat (see Example 2). Such a monoclonal antibody of the invention can, e.g. be produced by CDR grafting or by recombinant production of the antibody. Such methods are known in the art (see e.g. Queen, U.S. Pat. No. 5,585,089 and Winter, U.S. Pat. No. 5,225,539, Cabilly U.S. Pat. No. 4,816,567).

In another aspect, the inventions also relates to an anti-L1 monoclonal antibody, characterized in that at least one of its complementarity determining regions (CDRs)

-   -   a) has one of the following sequences QDISNY (SEQ ID NO: 7),         YTS, QQGNTLPWT (SEQ ID NO: 8), GYTFTRYW (SEQ ID NO: 9), INPRNDRT         (SEQ ID NO: 10), or ALGGGYAMDY (SEQ ID NO: 11) or     -   b) has a sequence which, in comparison to the sequences         mentioned under a) has at least         -   one conservative amino acid exchange.

These sequences show again the CDRs of the monoclonal antibody 9.3 (see FIG. 12), but the CDRs have been determined using another method known in the art, namely according to the IMGT® method from the international ImMunoGeneTics Information System®.

In an especially preferred aspect, the invention relates to a monoclonal antibody, produced by the hybridoma cell deposited under DSMZ ACC2841. This hybridoma cell has been deposited with the Deutsche Sammlung für Mikroorganismen und Zellen on Apr. 25, 2007 under the Budapest Treaty.

In another aspect, the invention relates to a humanized antibody based on the monoclonal antibody of the invention as described above.

Humanized antibodies are antibody molecules from non-human species having one or more complementarily determining regions (CDRs) from the non-human species and a framework region (FR) from a human immunoglobulin molecule. (See, e.g., Queen, U.S. Pat. No. 5,585,089 and Winter, U.S. Pat. No. 5,225,539.) Such chimeric and humanized monoclonal antibodies can be produced by recombinant DNA techniques known in the art.

In general, in order to obtain a humanised antibody, nucleic acid sequences encoding human variable heavy chains and variable light chains may be altered by replacing one or more CDR sequences of the human (acceptor) sequence by sequence encoding the respective CDR in the mouse antibody sequence (donor sequence). The human acceptor sequence may comprise FR derived from different genes.

In a preferred embodiment, the humanized antibody of the invention has at least one non-human CDR and human framework region (FR) residues.

Sequences encoding full length antibodies can be subsequently obtained by joining the rendered variable heavy and variable light chain sequences to human constant heavy chain and constant light chain regions. Preferred human constant light chain sequences include kappa and lambda constant light chain sequences. Preferred human constant heavy chain sequences include IgG1, IgG2 and sequences encoding IgG1 mutants which have rendered immune-stimulating properties. Such mutants may have a reduced ability to activate complement and/or antibody dependent cellular cytotoxicity and are described in U.S. Pat. No. 5,624,821; WO 99/58572, U.S. Pat. No. 6,737,056. An especially preferred constant heavy chain is an IgG1 comprising the substitutions E233P, L234V, L235A, A327G, A330S, P331S and a deletion of residue 236.

In another embodiment, the full length antibody comprises an IgA, IgD, IgE, IgM, IgY or IgW sequence.

Suitable human donor sequences can be determined by sequence comparison of the peptide sequences encoded by the mouse donor sequences to a group of human sequences, preferably to sequences encoded by human germ line immunoglobulin genes or mature antibody genes. A human sequence with a high sequence homology, preferably with the highest homology determined may serve as the acceptor sequence for the humanization process.

In addition to the exchange of human CDRs for mouse CDRs, further manipulations in the human donor sequence may be carried out to obtain a sequence encoding a humanized antibody with optimized properties (such as affinity of the antigen).

In a preferred example, heavy chain residues 31-35, 50-58 and 95-102 and residues 6, 23, 24, and 49 in the human acceptor sequence are altered to correspond to the respective residues of the mouse sequence (Adair, U.S. Pat. No. 5,859,205).

Furthermore the altered human acceptor antibody variable domain sequences may also be rendered to encode one or more amino acids (according to the Kabat numbering system) of position 4, 35, 38, 43, 44, 46, 58, 62, 64, 65, 66, 67, 68, 69, 73, 85, 98 of the light variable region and 2, 4, 36, 39, 43, 45, 69, 70, 74, 75, 76, 78, 92 of the heavy variable region corresponding to the mouse donor sequence (Carter and Presta, U.S. Pat. No. 6,407,213)

The humanisation of an mouse L1 antibody is described in Example 2.

Also the sequences of the CDRs may be altered, preferably by exchanges leading to a conservative amino acid exchange.

In general, manipulations may result in alterations in the FR as well as the CDR regions and include exchanges, deletions and insertion of residues. The alterations may be induced by random or directed mutagenesis. An antibody phage display system, as described before, may be employed for the selection of mutants with desired and/or improved properties

In another aspect the invention relates to a human antibody capable of recognizing the same epitope as the antibody 9.3. Methods for generating human antibodies are known in the art. These methods employ for example mice in which the endogenous immunoglobuline genes have been partially or completely inactivated and human immunoglobuline loci were introduced. Upon immunization with an immunogenic epitope, these mice are capable of producing human antibodies (U.S. Pat. Nos. 5,545,807; 5,545,806; 5,569,825; 5,589,369; 5,591,669; 5,625,126; 5,633,425; 5,661,016)

In a further preferred embodiment, the humanized antibody of the invention comprises the sequence of L1_(—)9.3hu or L1_(—)9.3hu3 as shown in FIGS. 8 a) and b).

In another aspect, the invention relates to a binding molecule comprising

-   -   a) at least one of the following sequences RASQDISNYLN (SEQ ID         NO: 1), YTSRLHS (SEQ ID NO: 2), QQGNTLPWT (SEQ ID NO: 3), RYWML         (SEQ ID NO: 4), EINPRNDRTNYNEKFKT (SEQ ID NO: 5), or GGGYAMDY         (SEQ ID NO: 6) or     -   b) at least one sequence which has in comparison to the         sequences given in a) at least one conservative amino acid         exchange.

As explained above, these sequences show the CDRs of the antibody 9.3 (see Example 2).

In another aspect, the invention relates to a binding molecule comprising

-   -   a) at least one of the following sequences QDISNY (SEQ ID NO:         7), YTS, QQGNTLPWT (SEQ ID NO: 8), GYTFTRYW (SEQ ID NO: 9),         INPRNDRT (SEQ ID NO: 10), or ALGGGYAMDY (SEQ ID NO: 11) or     -   b) at least one sequence which has in comparison to the         sequences given in a) at least one conservative amino acid         exchange.

As explained above, these sequences show again the CDRs of the monoclonal antibody 9.3, determined by another method known in the art.

According to the invention, a binding molecule is a molecule capable of binding L1. Preferably, the binding molecule is an immunoglobulin comprising molecule, i.e. comprises at least one Ig domain.

In a preferred embodiment, the binding molecule of the invention is selected from the group consisting of single chain antibodies (e.g. scFv, multimers of scFv like diabodies, triabodies or tetrabodies, antibody fragments (e.g. Fab), tandabs, flexibodies, bispecific antibodies, and chimeric antibodies.

The structure of an antibody and especially the function of its CDRs is known in the art (Carter P J. Potent antibody therapeutics by design. Nature Rev. Immunol. 6:343-357, 2006).

scFv and multimers thereof, tandabs, diabodies and flexibodies are standard antibody formats known in the art, e.g. from WO 88/1649, WO 93111161, WO 99/57150 and EP1293514B1.

In single chain Fv (scFv) the two antigen binding variable regions of the light and heavy chain (VH Fv and VL Fv) of an antibody are artificially connected by a linker peptide, designated as single chain variable fragment or single chain antibody (Bird, et al. (1988) Science 242:423-426; Orlandi, et al (1989) Proc Natl Acad Sci USA 86:3833-3837; Clarkson et al., Nature 352: 624-428 (1991)). The antigen binding site is made up of the variable domains of light and heavy chains of a monoclonal antibody. Several investigations have shown that the Fv fragment has indeed the full intrinsic antigen binding affinity of one binding site of the whole antibody.

In the context of this invention, diabodies are scFv with two binding specificities and can either be monospecific and bivalent or bispecific and bivalent.

Tandabs and flexibodies are further antibody formats which are e.g. defined in US2007031436 and EP1293514, respectively.

Antibody fragments that contain the idiotypes of the protein can be generated by techniques known in the art. For example, such fragments include, but are not limited to, the F(ab′)2 fragment which can be produced by pepsin digestion of the antibody molecule; the Fab′ fragment that can be generated by reducing the disulfide bridges of the F(ab′)2 fragment; the Fab fragment that can be generated by treating the antibody molecular with papain and a reducing agent; and Fv fragments.

A chimeric antibody is a molecule in which different portions are derived from different animal species, such as those having a variable region derived from a murine mAb and a human immunoglobulin constant region. (See, e.g., Cabilly et al., U.S. Pat. No. 4,816,567; and Boss et al., U.S. Pat. No. 4,816,397).

Bifunctional, or bispecific, antibodies have antigen binding sites of different specificities. Various forms of bispecific antibodies have been produced. These include BSIgG, which are IgG molecules comprising two distinct heavy chains and two distinct light chains that are secreted by so-called “hybrid hybridomas”, and heteroantibody conjugates produced by the chemical conjugation of antibodies or antibody fragments of different specificities (Segal D M, Weiner G J, Weiner L M. Bispecific antibodies in cancer therapy. Current Opin. Immunol. 11:558-562, 1999, Van Spriel A B, Van Ojik H H, Van de Winkel J G J. Immunotherapeutic perspective for bispecific antibodies. Immunology Today 21:391-397, 2000).

Bispecific antibodies have been generated to deliver cells, cytotoxins, or drugs to specific sites. An important use has been to deliver host cytotoxic cells, such as natural killer or cytotoxic T cells, to specific cellular targets. (P. J. Lachmann, Clin. Exp. Immunol. 79: 315 (1990)). Another important use has been to deliver cytotoxic proteins to specific cellular targets. (V. Raso, T. Griffin, Cancer Res. 41:2073 (1981); S. Honda, Y. Ichimori, S. Iwasa, Cytotechnology 4:59 (1990)). Another important use has been to deliver anti-cancer non-protein drugs to specific cellular targets (J. Corvalan, W. Smith, V. Gore, Intl. J. Cancer Suppl. 2:22 (1988); M. Pimm et al., British J. of Cancer 61:508 (1990)). Such bispecific antibodies have been prepared by chemical cross-linking (M. Brennan et al., Science 229:81 (1985)), disulfide exchange, or the production of hybrid-hybridomas (quadromas). Quadromas are constructed by fusing hybridomas that secrete two different types of antibodies against two different antigens (Kurokawa, T. et al., Biotechnology 7.1163 (1989)).

In a preferred embodiment of the invention, the antibody or binding molecule of the invention is linked to an active substance, preferably a toxin, a nanoparticle, a cytokine, or a radionuclide. Such antibody conjugates are known in the art (Wu AM, Senter PD. Arming antibodies: prospects and challenges for immunoconjugates. Nature Biotechnol. 23:1137-1146, 2005, Pastan I, Hassan R, FitzGerald D J, Kreitman R J. Immunotoxin treatment of cancer. Annu. Rev. Med. 58:221-237, 2007, WO 90/12592, WO 20071030642, WO 2004/067038. WO 2004/003183, US 200510074426, WO 94/04189).

In a preferred embodiment, the antibody or binding molecule of the invention binds L1 with an affinity (KD) of at least 10⁻⁸, preferably of at least 10⁻⁹, more preferably of at least 10⁻¹⁰ or 10⁻¹¹.

Preferably, the antibody of the invention does not significantly bind to other members of the L1-protein family as for example CHL1 (close homolog of L1, accession number NM_(—)006614), NrCAM (Neuronal cell adhesion protein, accession number NM_(—)001037132 or NM_(—)005010) and/or NFASC (Neurofascin, accession number NM_(—)015090). Preferably the antibody binds the other members of the L1-family with an at least 100-fold lower affinity, more preferably at least 1000-fold lower affinity compared to the affinity for L1. The affinity of the antibody for the different proteins can be determined for example by measuring the binding affinity to recombinant proteins as described in example 6. The binding of the antibody to the different L1 family members of the L1-family may also be determined by expressing said proteins on CHO cells and measuring the antibody binding by FACS analysis as described in Example 1.2 and Example 7.

It is one aspect of the invention that the antibody does not significantly increase the release of cytokines, e.g. tumour necrosis factor-alpha or interferon gamma. Preferably the release is not increased by more than 30%, more preferably not more than 20% and most preferably not more than 10%. The release of cytokines can be tested as described in Example 8. Alternatively the concentration of cytokines can be determined in the blood of an animal before and after the administration of the antibody. The cytokine concentration may be determined by an ELISA assay or other methods known in the art.

In another preferred embodiment the antibody does not significantly induce T-cell proliferation or inhibit T-cell proliferation. The effect of an antibody on T-cell proliferation can be determined as described in Example 9.

The invention further relates to a binding molecule which is capable of binding to the same L1 epitope recognized by the monoclonal antibody 9.3, produced by the hybridoma cell deposited under DSMZ ACC2841. Preferably, with respect to this binding molecule of the invention, the same embodiments defined with respect to the structure of the binding molecule described above also apply to this binding molecule of the invention.

Preferably, the binding of the antibody to the epitope is not significantly increased or decreased by the glycosylation state of the L1 protein. The influence of the glycosylation state on the antibody binding can be determined as described in Example 10.

Furthermore, the invention relates to a hybridoma cell that produces the monoclonal antibody of the invention.

Furthermore, the invention relates to the hybridoma cell deposited under DSMZ ACC2841.

As explained above and as described in the example section, the monoclonal antibody or binding molecule of the invention is especially suitable for the treatment of tumorigenic diseases.

Therefore, in another aspect, the invention relates to the use of the antibody of the invention or the binding molecule of the invention for the preparation of a medicament for the treatment of a tumorigenic disease.

Furthermore, the invention also relates to a method for treating a tumorigenic disease, wherein an antibody or binding molecule of the invention is administered to a subject in an effective amount to treat said disease. With respect to said method of the invention, all embodiments as defined below for the use of the invention also apply.

As mentioned above, in the art it has been suggested to use anti-L1 antibodies for sensitizing tumor cells for the treatment with a chemotherapeutic drug or with radiotherapy (see Sebens Müerkoster et al., Oncogene. 2007 Apr. 26; 26(19): 2759-68, Epub 2006 Nov. 6). Consequently, in another aspect, the present invention relates to the use of the antibody of the invention or the binding molecule of the invention for sensitizing tumor cells in a patient for the treatment with a chemotherapeutic drug or with radiotherapy.

This aspect of the present invention is especially useful in cases where the tumor cells are at least partially resistant to chemotherapy or to radiotherapy.

Therefore, in a preferred embodiment of the invention, the cells to be sensitized are at least partially resistant to the treatment with said chemotherapeutic drug or to radiotherapy.

In the context of the present invention, the term “sensitizing” is to be understood that after the treatment with the anti L1 antibody or binding molecule of the invention, the tumor cells are more susceptible to the treatment with a chemotherapeutic drug or with radiotherapy than before said treatment. This can e.g. be tested by isolating tumor cells from the patient and testing in vitro whether the treatment with said antibody or binding molecule of the invention results in a sensitization of the cells. This test can be performed as described in reference (Sebens Müerkoster et al., Oncogene. 2007 Apr. 26; 26(19): 2759-68, Epub 2006 Nov. 6).

In a preferred embodiment, the cells, before the administration of the anti L1 antibody or binding molecule of the invention, were not susceptible to the treatment or only susceptible to an extend that the treatment with a chemotherapeutic drug or with radiotherapy would not result in the desired therapeutic effect.

Preferably, with the help of the anti-L1 antibody or binding molecule of the invention, the susceptibility is increased by at least 20%, more preferably by at least 40% and even more preferably by at least 100%.

An overview over chemotherapeutic drugs and radiotherapy is e.g. given in Remmington's Pharmaceutical Sciences, 5^(th) ed., chapter 33, in particular pages 624 to 652.

Any of numerous chemotherapeutic drugs can be used in the methods or uses of the invention. These compounds fall into several different categories, including, for example, alkylating agents, antineoplastic antibiotics, antimetabolites, and natural source derivatives.

Examples of alkylating agents that can be used in the invention include busulfan, caroplatin, carmustine, chlorambucil, cisplatin, cyclophosphamide (i.e., cytoxan), dacarbazine, ifosfamide, loinustine, mecholarethamine, melphalan, procarbazine, streptozocin, and thiotepa.

Examples of antineoplastic antibiotics include bleomycin, dactinomycm, daunorubicin, doxorubicin, idarubicin, mitomycin (e.g., mitomycin C), mitoxantrone, pentostatin, and plicamycin.

Examples of antimetabolites include fluorodeoxyuridine, cladribine, cytarabine, floxuridine, fludarabine, fluorouracil (e.g., 5-fluorouracil (5FU)), gemcitabine, hydroxyurea, mercaptopurine, methotrexate, and thioguanine.

Examples of natural source derivatives include docetaxel, etoposide, irinotecan, taxanes (e.g. paclitaxel), teniposide, topotecan, vinblastine, vincristine, vinorelbine, prednisone, and tamoxifen.

Additional examples of chemotherapeutic agents that can be used in the invention include asparaginase and mitotane.

Furthermore, also C2 ceramide can be used.

In an especially preferred embodiment, the chemotherapeutic drug is selected from the group consisting of actinomycin-D, mitomycin C, cisplatin, doxorubicin, etoposide, verapamil, podophyllotoxin, 5-FU, taxans such as paclitaxel, and carboplatin.

According to the invention, the term “radiotherapy” refers to each radiation therapy which is commonly used to treat tumors cells. In a preferred embodiment, this therapy include γ-rays, X-rays, microwaves, UV radiation as well as the direct delivery of radio-isotopes to or next to tumor cells (brachytherapy).

As mentioned above, the object of this aspect of the invention is to sensitize tumor cells for the treatment with a chemotherapeutic drug or with radiotherapy. Consequently, in a preferred embodiment, after the sensitization with the anti L1 antibody or binding molecule of the invention, the patient is further treated with said chemotherapeutic drug or with said radiotherapy.

In the context of the present invention, it is envisaged to sensitize tumor cells of any cell type or to treat any tumorigenic disease. Preferably, the tumor cells or the tumorigenic disease are of a type selected from the group consisting of astrocytoma, oligodendroglioma, meningioma, neurofibroma, glioblastoma, ependymoma, Schwannoma, neurofibrosarcoma, medulloblastoma, melanoma, pancreatic cancer, prostate carcinoma, head and neck cancer, breast cancer, lung cancer, ovarian cancer, endometrial cancer, renal cancer, neuroblastomas, squamous cell carcinomas, medulloblastomas, hepatoma, colon cancer, and mesothelioma and epidermoid carcinoma.

Furthermore, it is preferred that the tumor cells are from an epithelial tumor or the tumorigenic disease is an epithelial tumor, preferably wherein the epithelial tumor is pancreatic cancer, colon cancer, ovarian cancer or endometrial cancer.

In a preferred embodiment the antibody does not induce neuronal side effects when administered in a therapeutically effective amount.

As discussed above, the anti-L1 antibody or binding molecule are used for the preparation of a pharmaceutical composition.

In general, the pharmaceutical compositions of the present invention comprise a therapeutically effective amount of a therapeutic, and a pharmaceutically acceptable carrier. In a specific embodiment, the term “pharmaceutically acceptable” means approved by a regulatory agency of the Federal or a state government or listed in the U.S. Pharmacopeia or other generally recognized pharmacopeia for use in animals, and more particularly, in humans. The term “carrier” refers to a diluent, adjuvant, excipient, or vehicle with which the therapeutic is administered. Such pharmaceutical carriers can be sterile liquids, such as water and oils, including those of petroleum, animal, vegetable or synthetic origin, including but not limited to peanut oil, soybean oil, mineral oil, sesame oil and the like. Water is a preferred carrier when the pharmaceutical composition is administered orally. Saline and aqueous dextrose are preferred carriers when the pharmaceutical composition is administered intravenously. Saline solutions and aqueous dextrose and glycerol solutions are preferably employed as liquid carriers for injectable solutions. Suitable pharmaceutical excipients include starch, glucose, lactose, sucrose, gelatin, malt, rice, flour, chalk, silica gel, sodium stearate, glycerol monostearate, talc, sodium chloride, dried skim milk, glycerol, propylene, glycol, water, ethanol and the like. The composition, if desired, can also contain minor amounts of wetting or emulsifying agents, or pH buffering agents. These compositions can take the form of solutions, suspensions, emulsions, tablets, pills, capsules, powders, sustained-release formulations and the like. The composition can be formulated as a suppository, with traditional binders and carriers such as triglycerides. Oral formulation can include standard carriers such as pharmaceutical grades of mannitol, lactose, starch, magnesium stearate, sodium saccharine, cellulose, magnesium carbonate, etc. Examples of suitable pharmaceutical carriers are described in “Remington's Pharmaceutical Sciences” by E. W. Martin. Such compositions will contain a therapeutically effective amount of the therapeutic, preferably in purified form, together with a suitable amount of carrier so as to provide the form for proper administration to the patient. The formulation should suit the mode of administration.

In a preferred embodiment, the composition is formulated, in accordance with routine procedures, as a pharmaceutical composition adapted for intravenous administration to human beings. Typically, compositions for intravenous administration are solutions in sterile isotonic aqueous buffer. Where necessary, the composition may also include a solubilizing agent and a local anesthetic such as lidocaine to ease pain at the site of the injection. Generally, the ingredients are supplied either separately or mixed together in unit dosage form, for example, as a dry lyophilized powder or water-free concentrate in a hermetically sealed container such as an ampoule or sachette indicating the quantity of active agent. Where the composition is to be administered by infusion, it can be dispensed with an infusion bottle containing sterile pharmaceutical grade water or saline. Where the composition is administered by injection, an ampoule of sterile water or saline for injection can be provided so that the ingredients may be mixed prior to administration.

The therapeutics of the invention can be formulated as neutral or salt forms. Pharmaceutically acceptable salts include those formed with free carboxyl groups such as those derived from hydrochloric, phosphoric, acetic, oxalic, tartaric acids, etc., those formed with free amine groups such as those derived from isopropylamine, triethylamine, 2-ethylamino ethanol, histidine, procaine, etc., and those derived from sodium potassium, ammonium, calcium, and ferric hydroxides, etc.

The amount of the therapeutic of the invention, which will be effective in the treatment of a particular disorder or condition, will depend on the nature of the disorder or condition, and can be determined by standard clinical techniques. In addition, in vitro assays may optionally be employed to help identify optimal dosage ranges. The precise dose to be employed in the formulation will also depend on the route of administration, and the seriousness of the disease or disorder, and should be decided according to the judgment of the practitioner and each patients circumstances. However, suitable dosage ranges for intravenous administration are generally about 20-500 micrograms of active compound per kilogram body weight. Suitable dosage ranges for intranasal administration are generally about 0.01 pg/kg body weight to 1 mg/kg body weight. Effective doses may be extrapolated from dose-response curves derived from in vitro or animal model test systems. In general, suppositories may contain active ingredient in the range of 0.5% to 10% by weight; oral formulations preferably contain 10% to 95% active ingredient.

Various delivery systems are known and can be used to administer a therapeutic of the invention, e.g., encapsulation in liposomes, microparticles, and microcapsules: use of recombinant cells capable of expressing the therapeutic, use of receptor-mediated endocytosis (e.g., Wu and Wu, 1987, J. Biol. Chem. 262:4429-4432); construction of a therapeutic nucleic acid as part of a retroviral or other vector, etc. Methods of introduction include but are not limited to intradermal, intramuscular, intraperitoneal, intravenous, subcutaneous, intranasal, epidural, and oral mutes. The compounds may be administered by any convenient route, for example by infusion, by bolus injection, by absorption through epithelial or mucocutaneous linings (e.g., oral, rectal and intestinal mucosa, etc.), and may be administered together with other biologically active agents. Administration can be systemic or local. In addition, it may be desirable to introduce the pharmaceutical compositions of the invention into the central nervous system by any suitable route, including intraventricular and intrathecal injection; intraventricular injection may be facilitated by an intraventricular catheter, for example, attached to a reservoir, such as an Ommaya reservoir. Pulmonary administration can also be employed, e.g., by use of an inhaler or nebulizer, and formulation with an aerosolizing agent.

In a specific embodiment, it may be desirable to administer the pharmaceutical compositions of the invention locally to the area in need of treatment. This may be achieved by, for example, and not by way of limitation, local infusion during surgery, topical application, e.g., in conjunction with a wound dressing after surgery, by injection, by means of a catheter, by means of a suppository, or by means of an implant, said implant being of a porous, non-porous, or gelatinous material, including membranes, such as sialastic membranes, or fibers. In one embodiment, administration can be by direct injection at the site (or former site) of a malignant tumor or neoplastic or pre-neoplastic tissue.

In another embodiment, the therapeutic can be delivered in a vesicle, in particular a liposome (Langer, 1990, Science 249:1527-1533), more particular a cationic liposome (WO 98/40052).

In yet another embodiment, the therapeutic can be delivered via a controlled release system. In one embodiment, a pump may be used (Langer, supra). In yet another embodiment, a controlled release system can be placed in proximity of the therapeutic target, thus requiring only a fraction of the systemic dose.

Within the context of this aspect of the invention, the invention also includes a method for sensitizing tumor cells in a patient for the treatment with a chemotherapeutic drug or with radiotherapy, comprising administering to the patient an efficient amount of an anti-L1 antibody or binding molecule of the invention. All embodiments described above also apply to this method of the invention.

Throughout the invention, the term “effective amount” means that a given molecule or compound is administered in an amount sufficient to obtain a desired therapeutic effect. In case that, throughout the invention, two compounds are administered in a therapeutic effective amount, this includes that one or each of the compounds is administered in a subtherapeutic amount, i.e. that the amount of each compound on its own is not sufficient to provide a therapeutic effect, but that the combination of the compounds results in the desired therapeutic effect. However, it is also included within the present invention that each of the compounds on its own is administered in a therapeutically effective amount.

In another aspect of the invention, the invention relates to the use of the anti-L1 antibody or binding molecule of the invention for the preparation of a medicament for the treatment of tumor cells in a patient previously treated with a chemotherapeutic drug or with radiotherapy.

As mentioned above, the treatment of tumor cells with anti-L1 antibodies has already been described in WO 02/04952 and WO 06/013051, incorporated herein by reference.

In the context of the present invention, the term “previously treated” may include patients which have already been treated with a chemotherapeutic drug or with radiotherapy in the course of a separated regimen which has taken place e.g. within the last six or eight months.

In the course of tumor treatment with chemotherapeutic drugs or radiotherapy it is in most cases observed that after an initial response of the tumor to such therapy (tumor mass reduction or stabilization of the disease) the tumors start to progress again. Such progression usually starts upon weeks or months after such therapy. Typically these tumors are then resistant to further treatment with the previously applied chemotherapeutic drug and other treatment modalities are wanted. As described above it has been found that such resistant tumors express L1 and therefore become a target for anti-L1 antibodies.

Therefore, according to this embodiment of the invention, the term “previously treated” preferably means that the patient previously received such treatment, such treatment showed an initial effect and—at the time of therapy with the anti-L1 antibody or the binding molecule the tumor is progressing again.

Furthermore, the term “previously treated” may also be seen in a context where the L1 anti-L1 antibody or the binding molecule and the chemotherapeutic drug or radiotherapy are used within the same regimen, meaning that the treatments are given within one treatment schedule. In this context “in one treatment schedule” means that the treatment are applied at the same time, one after another or intermittently, but—in contrast to above—time distances between the individual treatments are short (within one week or within 2-4 days) and, if a treatment success is seen, one does not wait for tumor progression before the next treatment is applied.

Preferably, in this context, the invention includes the case where a patient is treated with a chemotherapeutic drug or with radiotherapy and subsequently, preferably within one week or less and more preferably within 2-4 days, a treatment with the anti-L1 antibody or the binding molecule of the invention is started. In a further preferred embodiment several cycles of chemotherapy or radiotherapy on one side and treatment with the anti-L1 antibody or the binding molecule are made, with intervals of preferably one week or less and more preferably within 24 days.

In a preferred embodiment, the patient is at least partially resistant to the treatment with said chemotherapeutic drug or with radiotherapy, an effect often observed in the course of said treatment types (see above).

In a further aspect, the invention relates to the use of the anti-L1 antibody or the binding molecule of the invention for the preparation of a medicament for the treatment of tumor cells in a patient at least partially resistant to treatment with a given chemotherapeutic drug or with radiotherapy.

In the context of the present invention, the term “resistant to treatment” means that the respective tumor cell does not react to the treatment with a chemotherapeutic drug or with radiotherapy in a complete manner. Rattler, with respect to this tumor cell, treatment with said chemotherapeutic drug or radiotherapy is rather ineffective or even shows no effects.

In a further aspect of the invention, the invention relates to the use of the anti-L1 antibody or the binding molecule of the invention for the preparation of a medicament for the treatment of a tumorigenic disease, wherein the anti-L1 antibody or the binding molecule is administered in combination with a chemotherapeutic drug or with radiotherapy, preferably wherein the chemotherapeutic drug or the radiotherapy is administered prior to the anti-L1 antibody or binding molecule of the invention.

According to the invention, the term “treatment of tumorigenic disease” includes both the killing of tumor cells, the reduction of the proliferation of tumor cells (e.g. by at least 30%, at least 50% or at least 90%) as well as the complete inhibition of the proliferation of tumor cells. Furthermore, this term includes the prevention of a tumorigenic disease, e.g. by killing of cells that may or a prone to become a tumor cell in the future as well as the formation of metastases.

According to the invention, the term “in combination with” includes any combined administration of the anti-L1 antibody or the binding molecule and the chemotherapeutic drug of radiotherapy. This may include the simultaneous application of the drugs or radiotherapy or, preferably, a separate administration. In case that a separate administration is envisaged, one would preferably ensure that a significant period of time would not expire between the time of delivery, such that the anti-L1 antibody or the binding molecule and the chemotherapeutic drug or radiotherapy would still be able to exert an advantageously combined effect on the cell. In such instances, it is preferred that one would contact the cell with both agents within about one week, preferably within about 4 days, more preferably within about 12-36 hours of each other.

The rational behind this aspect of the invention is that the administration of chemotherapeutic drugs or the treatment with radiotherapy leads to an increase of L1 expression on the surface of the tumor cells which in turn makes the tumor cells a better target for the anti-L1 antibody or the binding molecule.

Therefore, this aspect of the invention also encompasses treatment regimens where an the anti-L1 antibody or the binding molecule is administered in combination with the chemotherapeutic drug or radiotherapy in various treatment cycles wherein each cycle may be separated by a period of time without treatment which may last e.g. for two weeks and wherein each cycle may involve the repeated administration of the anti-L1 antibody or the binding molecule and/or the chemotherapeutic drug or radiotherapy. For example such treatment cycle may encompass the treatment with a chemotherapeutic drug or with radiotherapy, followed by e.g. the twice application of the anti-L1 antibody or the binding molecule within 2 days.

Throughout the invention, the skilled person will understand that the individual therapy to be applied will depend on the e.g. physical conditions of the patient or on the severity of the disease and will therefore have to be adjusted on a case to case basis.

Especially in the course of such repeated treatment cycles, it is also envisaged within the present invention that the anti-L1 antibody or the binding molecule is administered prior to the chemotherapeutic drug or the radiotherapy.

In the context of the above aspects of the invention, the invention also relates to a method for treating tumor cells in a patient previously treated with a chemotherapeutic drug or with radiotherapy, comprising administering to the patient a therapeutically effective amount of the anti-L1 antibody or binding molecule of the invention. Furthermore, the invention relates to a method for treating tumor cells in a patient at least partially resistant to treatment with a given chemotherapeutic drug or with radiotherapy, comprising administering to the patient a therapeutically effective amount of the anti-L1 antibody or binding molecule of the invention. Furthermore, the invention relates to a method for treating tumor cells in a patient, comprising administering to the patient a therapeutically effective amount of the anti-L1 antibody or binding molecule of the invention in combination with a chemotherapeutic drug or with radiotherapy. Furthermore, the invention relates to a method for treating tumor cells in a patient, comprising administering to the patient a therapeutically effective amount of the anti-L1 antibody or binding molecule of the invention.

The antibody of the invention may also be used in a method for a diagnostic method to determine the level of the L1 protein in body tissues or fluids.

With respect to these methods of the invention, all embodiments described above for the other uses or methods of the invention also apply.

The invention also relates to the antibody or the binding molecule of the invention for use as a medicament for the treatment of a tumorigenic disease or for sensitizing of tumor cells in a patient for the treatment with a chemotherapeutic drug or with radiotherapy.

In a preferred embodiment, said use exhibits further the features as defined for the uses of the invention.

The invention also relates to pharmaceutical compositions comprising the antibody or binding molecule of the invention. With respect to said pharmaceutical composition, all embodiments described above also apply.

The invention is further illustrated by the following figures and examples which are not intended to limit the scope of the invention.

LEGENDS TO FIGURES AND TABLES

FIG. 1

(A) FACS analysis of CHO, CHO-L1, SKOV3ip and OVMz cells. Cells were stained with the indicated mAbs (10 μg/ml) for 30 min at 4° C. Followed by a secondary PE-conjugated mAb. (B) Western blot analysis. Cell lysates from CHO wt, CHO-L1, OVMz and SKOV3ip cells were transferred on a PVDF membrane and then incubated with the indicated mAb to L1 (1 μg/ml), followed by a POX-conjugated secondary mAb.

FIG. 2

(A) Effect of antibodies on Erk-phosphorylation in SKOV3ip cells. Cells were incubated for 24 h at 37° C. with the indicated purified antibodies to L1 (10 μg/ml) or isotype control IgG1. Cells were also treated with DMSO (vehicle), or the EK-specific inhibitor PD59098. Cell lysates were examined for phosphorylation of Erk. (B) Effect of antibodies on Erk phosphorylation in SKOV3ip cells. Fluorescent staining of antibody treated cells with a phospho-Erk specific antibody and an Alexa488-conjugated secondary mAb.

FIG. 3

Analysis of matrigel cell invasion. Antibody (10 μg/ml) treated SKOV3ip cells were seeded into a 4-well plate and allowed to invade into the matrigel for 20 h (5% CO₂; 37° C.).

FIG. 4

Differential gene expression in SKOV3ip cells. (A) SKOV3ip cells were transfected with L11-specific or scrambled siRNA and 72 h later mRNAs were isolated, transcribed to cDNA and used as template for qPCR (SYBRgreen analysis). (B) SKOV3ip cells were treated with the L1-9.3 mAb (10 μg/ml) or the control mAB IgG1 (10 μg/ml) and 96 h later mRNAs were isolated, transcribed to cDNA and analyzed by qPCR for the expression of the indicated genes (SYBRgreen analysis). (C) Differential gene expression of residual tumor cells. mRNAs from residual tumors were isolated from antibody treated animals, ascribed into cDNA and analyzed by qPCR for the expression of the indicated genes.

FIG. 5

Tumor growth in nude mice. LacZ-tagged SKOV3ip cells were injected i.p. into nude mice and after tumor implantation animals were treated with the indicated L1 mAbs or control mAb EpCAM (Hea125). After 30 days the tumor volume was determined and is given as the ratio between X-Gal stained tumor mass and the total situs. 6 animals were analyzed per group.

FIG. 6

(A) Western blot analysis of L1-V5 constructs. Supernatant of transfected Sf9 insect cells were received from Ricardo Gouveia and analyzed by Western blot using L1-9.3 mAb and reprobed by anti-VS mAb. (B) Western blot analysis of L1-FC constructs. L1-FC constructs were transfected into Cos-7 cells using Jet PEI™ transfection reagent as described. After 3 days supernatants were purified using SepharoseA and analyzed by Western blot using L1-9.3 mAb.

FIG. 7

Homophilic cell adhesion assay. (A) The binding of J558-L1 cells was analyzed by bright field microscopy. One example of each treatment is shown here. In the red box coating with L1-Fc (10 μg/ml) is highlighted and in the black box the both controls, fibronectin (10 μg/ml) and BSA, are shown. 3) The graph shows the mean±SD of bound cells after the indicated antibody or control treatment.

FIG. 8

The antibody light chain and heavy chain DNA sequences used to construct the humanized antibodies are provided in FIGS. 8 a (SEQ ID NOS 17-21, respectively, in order of appearance) and 8b (SEQ ID NOS 22-25, respectively, in order of appearance) respectively.

FIG. 9

Amino acid sequences of: (a) the murine L1_(—)9.3 scFv (SEQ ID NO: 26); (b) the humanized L1_(—)9.3Hu (SEQ ID NO: 27); and (c) L1_(—)9.3Hu3 scFvs (SEQ ID NO: 28).

FIG. 10

DNA and amino acid sequences of the expressed portions of constructs: (a) L1_(—)9.3 [[(a)]] (SEQ ID NOS 29-30, respectively) (b) LI-9.3Hu [[(b)]] (SEQ ID NOS 31-32, respectively); and (c) L1_(—)9.3Hu3 scFv (SEQ ID NOS 33-34, respectively).

FIG. 11

Binding of the L1_(—)9.3, L1_(—)9.3Hu and L1_(—)9.3Hu3 scFvs to the human L1 cancer antigen. Rows A, B and C are coated with L1 and rows D, E and F are coated with streptavidin. The blue colour in the wells indicates binding of the individual scFv to the L1 on the plate. The lack of colour in the streptavidin coated rows shows that the single chain antibodies are specifically binding to L1

FIG. 12

Genomic sequences of the variable domains of the monoclonal antibody 9.3

a) Sequence of the kappa chain variable region (SEQ ID NO: 35) (dotted lines: CDR1, dashed lines: 15 CDR2, underlined: CDR3)

b) Sequence of the heavy chain variable region (SEQ ID NO: 36) (dotted lines: CDR1, dashed lines: CDR2, underlined: CDR3)

FIG. 13

A) Human PBMC and L1-positive OVMZ tumor cells were incubated with L1-9.3 mAb for 24 h and the amount of bound antibody was determined by FACS analysis.

B) The dissociation constants K_(D) were estimated from the regression curves using the concentration at half-maximal binding.

FIG. 14

L1-9.3 has no effect on the release of cytokines by resting and activated human PBMC. Cytokine levels of resting and OKT3-activated PBMC from three different donors were determined after an incubation for 24 h in presence or absence of 20 μg/ml L1-9.3. Ionomycin/PMA and LPS were used as stimulation controls. Results for IFN-γ (A) and TNF-α (B) are shown.

FIG. 15

L1-9.3 does not induce T cell proliferation and has no effect on OKT3-induced T cell proliferation. Proliferation of OKT3-activated PBMC from two different donors was determined in presence or absence of 20 μg/ml L1-9.3 using a BrdU incorporation assay 48 h post stimulation. There was no difference, whether the antibody was added prior, in parallel or after stimulation with 75 ng/ml OKT3. L1-9.3 by itself did not result in T cell activation.

FIG. 16

L1-9-3 was unaffected by deglycosylation of L1. The Western blot staining of L1 in untreated and deglycosylated cell lysate is shown using several different anti-L1 mAbs. The tested antibodies can be divided into three classes in respect to their glycosylation-dependency: First class (unaffected by glycosylation): L1-9.3. Second class (binding in WB was negatively affected by deglycosylation): 11A, 14.10, OV52.24 and OV549.20. Third class (binding in WB was positively affected by deglycosylation): 35.9 and 38.12.

FIG. 17

The figure shows in vivo binding of intravenously applied L1-9.3 to collecting ducts of the kidney. In vivo binding was only detectable using the amplification system CSA (FIG. 17A), while by using the conventional ABC-method, no signal was visible (FIG. 17B). Hence, L1-9.3 was detected in a range of 30-300 pmol in the tissue (L1-9.3 concentration is presumably higher than 5 ng/ml and below 50 ng/ml). Negative control did not show staining, thus, unspecific staining can be excluded (FIG. 17C). The staining pattern of in vivo bound L1-9.3 (FIG. 17A) corresponds to the L1 expression pattern in the kidney when directly staining tissue sections with L1-9.3 (FIG. 17D).

FIG. 18

FACS Analysis of Humanized L1-9.3 mAbs

Flow cytometry analysis of SKOV3ip pcDNA3.1 luciferase cells. Cells were stained with the indicated humanized mAbs (10 μg/ml) for 30 min 4° C., followed by a secondary PE-conjugated mAb.

FIG. 19

Mouse SKOV3ip Xenograft-Model

7*10⁶ SKOV3ip pcDNA3.1 luciferase cells were injected intraperitoneal into 6 weeks old CD1 nu/nu female mice. After 24 h mice were randomized in groups of 10 mice. Each group of mice was three times weekly injected with 300 μg either mAb L1-chi9.3, mAbL1-hu3 or PBS intraperitoneally.

On day 33 mice were imaged (FIG. 2). Tumor volume was determined using the XENOGEN IVIS 200 System. In brief, mice were anesthetised and injected with Luciferin D (3 μg/mouse) intraperitoneally. Afterwards, luciferase activity of the tumor cells was measured by detecting light emission. The tumor volume is shown as photon per second (total flux). Statistical analysis was done using the student's t-test.

FIG. 20

In vivo Total Tumor Mass

After 36 days mice were sacrificed and the tumor mass was determined. Tumor growth is given as a ratio of tumor mass to bodyweight. (A individual mice, B mean value). Statistical analysis was done using the student's t-test. Thus, the treatment of immunodeficient mice with L1 9.3 antibody could be reproduced with chimarised and humanized forms of the L1 9.3 mAb.

FIG. 21

PT45-P1res cells were either left untreated (w/o) or were treated with 20 μg/mL gemcitabone (A) or etoposide (B) in the absence (w/o) or presence of either 1 or 10 μg/mL anti L1CAM antibody 9.3 or 1 or 10 μg/mL isotype matched control antibody.

After 24 hours, cells were analysed by caspase-3/-7 assay. Means±SD from three independent experiments are shown. * indicates p<0.05.

FIG. 22

Colo357 cells were either left untreated (w/o) or were treated with 20 μg/mL gemcitabone (A) or etoposide (B) in the absence (w/o) or presence of either 1 or 10 μg/mL anti L1 CAM antibody 9.3 or 1 or 10 μg/mL isotype matched control antibody. After 24 hours, cells were analysed by caspase-3/-7 assay. Means±SD from three independent experiments are shown. * indicates p<0.05.

TABLE 1

The table shows a summary of antibodies tested in the indicated assays.

EXAMPLES 1. Example 1 1.1 Summary of Example 1

The L1 adhesion molecule (L1-CAM) is a transmembrane cell adhesion molecule involved in cell migration and axon guidance in the developing nervous system. L1 is also overexpressed in ovarian and endometrial carcinomas. Here L1 expression is associated with poor prognosis. In carcinoma cell lines, L1 over-expression augments cell motility, tumor growth in mice and induces expression of Erk-dependent genes. Here we show that treatment with antibodies to L1 abrogates Erk-activation, blocks cell invasion to matrigel and decreases tumor growth in nude mice. In cells treated with L1 antibodies the induction of Erk-dependent genes such as HOX A9, β3 integrin and IER 3 are reversed in vitro and in vivo. In this report, we demonstrate that the antibody L1-9.3 is the best therapeutic antibody of all tested L1 antibodies. In all cases L1-9.3 showed the best results concerning the invasive phenotype or therapeutic effect on tumor growth. We could show that L1-9.3 binds to the first Ig-like domain of L1 and can block the L1-L1 homophilic binding. The blocking of homophilic binding was only observed with L1-9.3. We conclude, that L1-9.3 is superior in therapy as it combines two functions: it blocks erk activation and interferes with the binding function of L1.

1.2 Results of Example 1

1.2.1 FACS Analysis of the new L1 Antibodies

Using immunization with a recombinant L1-Fc fusion protein, we generated novel L1 antibodies L1-9.3, L1-14.10, L1-35.9 and L1-38.12. To elucidate the specificity for L1 the new L1 mAbs were tested these antibodies on the endogenous L1 expressing ovarian carcinoma cell lines OVMz and SKOV3ip and the chinese hamster ovary cells CHO and stably transduced CHO-L1 cells by fluorescent staining (FIG. 1A) and Western blot analysis (FIG. 1B). All tested antibodies showed a positive staining of L1 in CHO-L1 cells (FIG. 1A). The staining pattern for the OVMz and the SKOV3ip cells was different for the antibodies. Interestingly, the L1-9.3 antibody showed bright staining of both ovarian carcinoma cell lines OVMz and SKOV3ip, whereas the L1-14.10 showed a very weak staining (FIG. 1A). The two L1 antibodies L1-35.9 and L1-38.12 could not bind to the endogenous L1 of these cells (FIG. 1A). As expected, no staining for L1 could be observed in CHO cells which we used as negative control. All new antibodies detected the full length L1 in CHO-L1, OVMz and SKOV3ip cell lysates by Western blot analysis. The L1-negative CHO cells served again as negative control.

1.2.2 The Erk Phosphorylation is Decreased after Antibody Treatment

A recent report has shown that expression of L1 in cooperation with serum-derived growth factors lead to sustained Erk-activation and the induction of Erk-dependent genes (Silletti et al, 2004). We investigated if the suppressive effect of L1-antibodies might be due to interference with L1-mediated gene regulation. Therefore we examined the mode of action of L1 antibodies using SKOV3ip cells. The mAbs L1-11A, L1-9.3 and L1-14.10 efficiently blocked Erk-phosphorylation (FIG. 2A) in vitro. There was no inhibition with isotype matched control mAb, DMSO as vehicle or the L1 antibody L1-38.12 (FIG. 2A) that can bind only the neural isoform of L1. Fluorescent analysis with the phospho-specific Erk antibody confirmed a clear reduction of activated Erk. A depletion from the nucleus in L1-mAb treated cells (L1-11A, L1-9.3 and L1-14.10) could also be observed (FIG. 2B).

1.2.3 Antibody Treatment with L1-Antibodies Reduced Cell Invasion

It has been demonstrated before that treatment with an antibody to L1 (L1-11A) reduced the haptotactic cell migration on fibronectin and the matrigel invasion of different cell lines (Arlt et al, 2006). We compared the invasion capacity of SKOV3ip cells treated with the different L1 antibodies. The antibodies L1-11A, L1-14.10 and especially L1-9.3 reduced the invasion of the SKOV3ip (FIG. 3). In sharp contrast, cells treated with the antibodies L1-35.9 or L1-38.12 did not show a reduction of invasion (FIG. 3).

1.2.4 Antibodies to L1 Affect Gene Expression In Vitro and In Vivo

We fisher examined whether antibodies to L1 affect the gene expression profile in SKOV3ip cells in vitro in a similar fashion as observed for siRNA-mediated depletion of L1 (FIG. 4A). Indeed, qRT-PCR analysis of cells treated with L1-9.3 or L1-11A versus control antibody showed significant changes in the expression of L1-regulated genes such as β3 integrin, the transcription factors HOXA9 and the apoptosis-related genes IER 3 and STK 39 (FIG. 4A). The same set of genes was downregulated in SKOV3ip cells transduced with a L1-specific siRNA (FIG. 4B).

We tested whether mAb L1-9.3 could also influence the gene expression profile of SKOV3ip cells in vivo similar to that observed in vitro. To this end, mRNA from residual tumors of L1-9.3 treated mice or IgG control treated mice were isolated and subjected to qRT-PCR analysis. L1-9.3 treatment led to significant regulation of L1-dependent genes as demonstrated for 110×A9, β3 integrin and IER 3 (FIG. 4C).

1.2.5 Analysis of Tumorigenicity in Nude Mice

Next, we investigated whether the intraperitoneal growth of SKOV3ip in mice could be inhibited by treatment with the mAbs L1-11A, L1-9.3 or L1-14.10. SKOV3ip-lacZ cells were injected into the peritoneal cavity of female nude mice 2 days before the onset of therapy. Biweekly i.p. treatments were done using the 10 mg/kg antibody concentration. Control mice were treated with PBS or HEA125 (anti EpCAM) as a control antibody (biweekly 10 mg/kg i.p.). In all anti-L1 mAb treatment groups, a substantial decrease in the amount of tumor mass was visible compared with PBS or the control antibody HEA-125 (FIG. 5). Compared with the control, all anti-L1 mAbs led to a dose-dependent reduction of i.p. tumor burden [L1-11A (10 mg/kg), −40%; L1-14.10 (10 mg/kg), −30%; L1-9.3 (10 mg/kg), −60%; FIG. 5]. Tumor reduction in the group treated with the L1-9.3 (10 mg/kg) was statistically significant (P_(L1-9.3 (10 mg/kg))=0.004) compared with the PBS control. Mice treated with the HEA125 control antibody revealed no detectable reduction of SKOV3ip-lacZ i.p. tumor burden compared with the PBS-treated group (FIG. 5), although EpCAM is present on the SKOV3ip cells and HEA125 can bind to the tumor cells. No side effects or severe toxicity of L1-mAbs L1-11A, L1-9.3 or L1-14.10 treatment was observed during the whole course of treatment.

Thus, treatment with antibodies to L1 reduced the tumor growth SKOV3ip cells (FIG. 5) suggesting that antibodies to L1 can regulate gene expression but also affect in vivo tumor growth.

1.2.6 Biacore Studies of the New L1 Antibodies

This study was performed by Avidex (Oxford) as described in Example 6. Table 1 summarizes these results concerning the binding kinetics of the new L1 antibodies (ka, kd and KD).

1.2.7 Epitope-Mapping of L1-9.3 Binding Site

An important factor for the characterization of novel L1 antibodies is to examine their binding sites in L1. Therefore, we constructed a variety of L1-Fc fusion proteins covering different parts of the molecule. PCR products were amplified coding different length of L1 ectodomain regions. These constructs were cloned into the pIg vector, and expressed as Fc-fusion proteins. After purification, products were used for Western blot analysis. For comparing the results, we analyzed other recombinant L1 protein fragments (obtained from Ricardo Gouveia, Oeiras, Portugal), L1-9.3 was found to bind to first Ig domain of L1 (FIG. 6). L1-14.10 binds in the third Ig domain whereas L1-11A binds between the FN3-5 site (FIG. 6).

1.2.8 mAB L1-9.3 Blocks L1-L1 Homophilic Binding

We asked if the L1 antibodies could interfere with the homophilic binding function of L1. To address this question, we used a cell adhesion assay in which L1-transfected cells are allowed to bind to immobilized L1. After initial coating of glass slides with a recombinant L1-Fc fusion protein, fibronectin for positive control (to which cells bind in an integrin dependent manner) or BSA as a negative control, we incubated J558-L1 cells with L1-11A, L1-9.3 or L1-14.10 antibody. For control, we used an IgG-control, PBS or an antibody to CD24 (SWA11). The mAb L1-9.3 could completely block the L1-L1 homophilic binding, whereas all other tested antibodies could not interfere with the homophilic binding capacity. None of the antibodies interfered with the binding to fibronectin (data not shown).

1.3 Materials and Methods

1.3.1 Cell Lines and Cell Culture

The human ovarian carcinoma cell lines SKOV3ip (kindly provided by Ellen Vitetta, University of Texas, Dallas, Tex.) and OVMz were grown in DMEM (Biochrom, Berlin, Germany) with 10% FCS under cell culture conditions (5% CO₂, 95% relative humidity, 37° C.). For identification and quantification of tumor mass, the SKOV3ip cells were stably transduced with a lacZ-encoding retroviral vector (GeneSuppressor Retroviral System, Biocarta, Hamburg, Germany). The chinese hamster ovary cell line CHO stably expressing human L1 (−hL1) were established by transfection with superfect (Stratagene, Heidelberg, Germany) and selection for L1 expression with mAb L1-11A and magnetic beads (Myltenyi Biotec, Bergisch Gladbach, Germany) or sorting with FACS Calibur. All cells were cultivated in DMEM supplemented with 10% FCS at 37° C., 5% CO₂ and 100% humidity. Human L1 encoding plasmids and J558-L1 cells were obtained from Dr. Vance Lemmon (University of Miami, Miami, Fla., USA).

1.3.2 Antibodies

HEA-125, a mouse IgG1 directed against EpCAM, was described before and binds to all human adenocarcinomas (Moldenhauer et al., 1987). Monoclonal antibody L1-14.10 (Huszar et al., 2006), L1-9.3, L1-35.9 and L1-38.12 were obtained after immunization of mice with human L1-Fc protein comprising the ectodomain of L1 (Oleszewski et al., 1999). Goat anti-mouse IgG was affinity purified and absorbed to human serum proteins (Zymed Laboratories, Inc., San Francisco: Calif.).

1.3.3 Biochemical Analysis

SDS-PAGE and transfer of separated proteins to Immobilon membranes using semi-dry blotting were described before (Gutwein et al., 2000). After blocking with 5% slim milk in TBS or 1% BSA in TBS/0.1% Tween-20, the blots were developed with the respective primary antibody followed by peroxidase conjugated secondary antibody and ECL detection.

1.3.4 FACS Analysis

The surface staining of cells with saturating amounts of mAbs, either hybridoma supernatants or purified antibodies, and PE-conjugated goat antibodies to mouse Ig (Dianova, Hamburg, Germany) has been described elsewhere (Ebeling et al., 1996). Stained cells were analyzed with a FACScan (Becton Dickinson).

1.3.5 Immunofluorescence

For immunofluorescent staining, cells were grown on coverslips, treated for 10 min with pervanadate and fixed for 20 min with 4% paraformaldehyde/PBS at room temperature. Cells were washed in PBS and permeabilized with 0.1% NP-40 in PBS containing 5% goat serum for 15 min at room temperature. Cells were then incubated for 1 hour with first antibody (phospho-specific Erk1/2). After 3 washing steps with PBS cells were incubated 30 min in the dark to a second Alexa488-conjugated goat anti-mouse IgG. After washing the cells twice with PBS, stained cells were mounted on glass slides and examined with an epifluorescence microscope (Axioplan-2; Zeiss, Oberkochem).

1.3.6 Invasion Assay

Tumor cell invasion in vitro was determined in a double-filter assay as described previously in Erkell et al. (1988). Briefly, a Matrigel was layered between two filters, a lower 5 μm pore nitrocellulose filter and an upper 8 μm pore polycarbonate filter. Following incubation of 10⁵ cells with the filter sandwich for 20 h in 1 ml medium, the sandwich was fixed and the filters separated and stained with DAPI. Cells present in the gel on the lower filter were counted, and cell invasion was expressed as the ration of the cell number on the lower filter to the total number of cells present on both filters.

1.3.7 Quantitative PCR

For qPCR the cDNA was purified on Microspin G-50 columns (GE Healthcare, München, Germany) and quantitated by NanoDrop spectrophotometer (ND-1000. Kisker-Biotechnology, Steinfurt, Germany). Primers for qPCR were designed with the DNA Star Program and were produced by MWG (Ebersberg, Germany). β-actin was used as an internal standard. The PCR reaction was performed with the SYBRgreen mastemrix (Applied biosystems, Darmstadt, Germany).

1.3.8 Cell Binding Assay

Cell binding assays to L1-Fc or fibronectin are described in detail in Oleszewski et al (JCB 2000).

1.3.9 Tumor Model and Therapy

Pathogen-free, female athymic CD1 nu/nu mice (7-9 weeks old; 20 g on average; Charles River) were inoculated with 5×10⁶ human lacZ-tagged ovarian carcinoma cells (SKOV3ip-lacZ) into the peritoneal cavity at day 0, leading to i.p. tumor formation within 5 weeks. Anti-L1 mAbs were diluted in sterile PBS to the concentration needed for treatment. Tumor-bearing mice were treated i.p. twice weekly with a 300 μL solution of the respective dosage (10 mg/kg per application, respectively), vehicle (PBS), or Hea125 antibody control. Antibody treatments started from day 3 after tumor cell injection to give the tumor cells time to attach to the inner side of the abdominal wall and the surfaces of the i.p. organs. At autopsy (day 38), ascites was sampled from all mice amid the volume was determined. All i.p. organs (including tumor mass), the abdominal wall, and the diaphragm were removed, stained with β-galactosidase substrate (X-gal; Roche-Diagnostics, Penzberg, Germany), photographed, and weighed. The indigo blue tumor mass between the organs, on the diaphragm and the inner site of the abdominal wall, was removed and weighed alone. The relative tumor burden in each mouse was calculated by dividing tumor mass weight by total situs weight.

2. Example 2 Humanization of the Anti-L1 Murine Antibody L1_(—)9.3

In order to humanize the murine anti-L1 antibody L1_(—)9.3, the genes of human v-kappa 1 (humκ1), and variable heavy chain family III (humIII) were utilised as the acceptor sequences. The numbering system used herein for these genes is adopted from Wu and Kabat (Kabat, E. A: Wu, T. T., Perry, H M, Gottesman, K S and Foeller, C (1992) Sequences of proteins of immunological interest, Diane Books Publishing company). The murine L1_(—)9.3 antibody light and heavy chain amino acid sequences were aligned against the no acid sequences of the humκ1 light chain and the humIII heavy chain respectively. Two humanized L1_(—)9.3 antibodies (L1-9.3Hu and L1_(—)9.3Hu3) were generated by replacing the six CDRs of the human antibody with the corresponding CDRs from the murine L1_(—)9.3 antibody.

Locations of the Six Complementarity Determining Regions (CDRs)

Kabat numbering Loop scheme LCDR1 L24--L34 LCDR2 L50--L56 LCDR3 L89--L97 HCDR1 H31--H35B HCDR2 H50--H65 HCDR3 H93--H101

A number of framework residues of the murine L1-9.3 antibody were transferred to the humanized L1_(—)9.3 antibodies:

Version 1 (L1_(—9.3)Hu) humanized antibody—heavy chain residue numbers 6, 23, 27, 30, 43, 49, 71, 73, 76, 78 and 94, and light chain residue number 100 were transferred from the murine L1-9.3 antibody and light chain residue number 73 was replaced with the corresponding (Phe) found at this position in the human REI antibody light chain.

Version 2 (L1_(—)9.3Hu3) humanized antibody—heavy chain residue numbers 6, 23, 27, 30, 71, 73, and 94, and light chain residue number 100 were transferred from the murine L1_(—)9.3 antibody.

DNA sequences encoding single-chain variable fragment (scFv) analogues of the murine L1_(—)9.3 antibody and the two humanised versions of this antibody (L1_(—)9.3Hu, and L1_(—)9.3Hu3) for expression in E. coli were then generated. All of these scFvs contain the same linker (TSGPGDGGKGGPGKGPGGEGTKGTGPGG (SEQ ID NO: 12)). The scFv genes were synthesized by GeneArt AG, Germany.

The antibody light chain and heavy chain DNA sequences used to construct the humanized antibodies are provided in FIGS. 8 a and 8 b respectively.

FIGS. 9 a-9 c provide the amino acid sequences of the murine L1_(—)9.3 scFv and the humanized L1_(—)9.3Hu and L1_(—)9.3Hu3 scFvs respectively.

3. Example 3 Cloning of DNA Encoding the L1_(—)9.3, L1_(—)9.3Hu and L1 9.3Hu3 scFvs into E. coli Periplasmic Expression Vectors and Transformation of E. coli with These Vectors

Periplasmic expressed of scFvs is beneficial for a number of reasons. Firstly, such scFvs leak into the bacterial supernatant and from there can conveniently be assayed for binding to their cognate antigen (The L1 cancer antigen in this case). Secondly, periplasmic expression allows for purification of soluble active scFvs.

The DNA sequences encoding the L1_(—)9.3, L1-9.3Hu and L1_(—)9.3Hu3 scFvs as synthesized by GeneArt AG, Germany were not supplied in an E. coli periplasmic expression vector. Therefore, these DNA sequences where cloned into an E. coli periplasmic expression vector using the following methods.

The DNA encoding the synthesized scFvs were PCR rescued with the following primer pairs using standard PCR conditions and reagents:

scFv Primer pair L1_9.3 Yol811 and Yol812 L1-9.3Hu Yol813 and Yol814 L1_9.3Hu3 Yol813 and Yol814

The primer sequences are shown below.

Yol811 (SEQ ID NO: 13) AGCCGGCCATGGCCGATATTCAGATGACCCAGAC Yol812 (SEQ ID NO: 14) TCTATGCAGCGGCGGCACCGCCGCTGCTCACGGTAACGCTG Yol813 (SEQ ID NO: 15) AGCCGGCCATGGCCGATATTCAGATGACCCAGAG Yol814 (SEQ ID NO: 16) TCTATGCAGCGGCCGCACCGCCGCTGCTCACGGTAACCAGGGTG

The PCR products were run on a 1.6% agarose gel and bands of the correct size excised and purified. The PCR products were double digested with Nco1 and Not1 restriction enzymes under standard conditions followed by re-purification. The PCR products were ligated into an IPTG inducible periplasmic expression vector which contained:

-   -   a pelB leader sequence to direct the encoded polypeptides to the         periplasm where this leader sequence is then cleaved off     -   Nco1/Not1 cloning sites     -   the human antibody kappa chain constant region

The ligated vectors were transformed into E. coli TG1 cells and plated on of 2×TY agar (Bacto Trypton 16 g/L, yeast extract 10 g/L, 15 g/L bactoagar and NaCl 5 g/L) supplemented with 100 μg/ml ampicillin and 2% glucose. The DNA and amino acid sequences of the expressed portions of L1_(—)9.3, L1_(—)9.3Hu and L1 9.3Hu3 scFv constructs are shown in FIGS. 10 a, 10 b and 10 c respectively.

4. Example 4 Expression of L19.3, L1_(—)9.3Hu and L1_(—)9.3Hu3 Single-Chain Antibodies in E. coli

The polypeptides expressed by these vectors include the human antibody c kappa constant region fused to the C termini of the scFvs. These c kappa constant chain containing constructs are referred to herein as single chain antibodies.

Eight E. coli clones for each single chain antibody construct, L1_(—)9.3, L1_(—)9.3Hu, and L1_(—)9Hu3, (24 clones in total) were picked into separate wells of a 96 well plate containing 300 μl of 2×TY (Bacto Trypton 16 g/L, yeast extract 10 g/L and NaCl 5 g/L) supplemented with 100 g/ml ampicillin and 2% glucose. Each well has a 1 ml volume. The cultures were grown with shaking (200 rpm) at 37° C. until the cultures reached an OD₆₀₀ of approximately 0.5. The 96 well plates were then spun down at 3200 rpm for 10 min and the supernatant was aspirated and discarded. The bacterial pellets were resuspended in fresh 2×TY 400 μl supplemented with 100 μg/ml ampicillin and 1 mM IPTG to induce expression of the single chain antibodies. The cultures were shaken at 200 rpm overnight at 25° C.

The following day the 96 well plate was spun down at 3200 rpm for 10 min to pellet the cells. The supernatant containing the expressed L1 single chain antibodies was kept for ELISA analysis.

5. Example 5 ELISA Assay of Binding of the L1_(—)9.3, L1_(—)9.3Hu and L1_(—)9.3Hu3 scFvs to Human L1 Cancer Antigen

This ELISA assay was carried out in order to confirm that the humanisation process had not lead to a loss of antibody binding to the L1 cancer antigen and to identify which of the clones picked correctly expressed the single chain antibody constructs.

Three rows of a 96 well plate were coated with 100 μl L1 antigen comprising the extracellular domain of the L1 protein fused to an Fc fragment (5 μg/ml) in PBS for 1 hr at room temperature. A further three rows were coated with streptavidin (5 μg/ml) in PBS as a control.

The wells were washed tree times with 370 μl of PBS and blocked with 3% milk powder in PBS for 1 hr at room temperature.

50 μl of each overnight bacterial supernatant was mixed with 50 μl of 6% milk powder in PBS for 1 hour.

The blocked ELISA plate was washed twice with PBS as described above and the blocked supernatants containing single chain antibody were added and incubated for 1 hp at room temperature.

The 96 well plate was washed four times with PBS 0.1% tween followed by the addition of 100 μl of anti-human kappa light chains bound and free antibody HRP conjugate (Sigma A7164) 1:5000 dilution in PBS 1% BSA. The conjugate was incubated for 1 hr at room temperature followed by five washes with PBS 0.1% tween.

The ELISA was developed by the addition of TMB 2-Component Microwell Peroxidase Substrate Kit (Kirkegaard and Perry Laboratories Inc., USA) according to the manufacturer's protocol. An image of the ELISA plate is shown in FIG. 4. At least four L1 binding clones have been observed for each of three single chain antibody versions. These L1 binding single chain antibody clones do not bind to streptavidin.

FIG. 11 shows the binding of the L1_(—)9.3, L1_(—)9.3Hu and L1_(—)9.3Hu3 scFvs to the human L1 cancer antigen. Rows A, B and C are coated with L1 and rows D, E and F are coated with streptavidin. The blue colour in the wells indicates binding of the individual scFv to the L1 on the plate. The lack of colour in the streptavidin coated rows shows that the single chain antibodies are specifically binding to L1.

6. Example 6 Determination of Binding Affinity

Mouse antibody L1-9.3 and humanised antibody L1-hu3 were assayed by Biacore analysis (Biacore AB, Uppsala, Sweden) to determine binding kinetics.

A BIAcore CM5 sensor chip was activated with EDC/NHS and purified recombinant L1-Fc extracellular fragment (515 μg/ml in PBS) was coupled to the CM5 sensor chip to between 200 and 3000 RU. The remaining active sites were blocked by ethanolamine/HCl. Antibody binding was measured by adding antibody at concentrations from 6 to 3333 nM at a flow rate of 10 ul/min using the Kinject function. The chip was regenerated with 10 mM Glycine pH2.0 with 500 mM NaCl to remove the bound antibodies.

The binding curves were fit to a Langmuir binding model using BIAevaluation software (Biacore AB, Uppsala, Sweden). Determined KD values are shown in Table 2.

TABLE 2 Antibody L1-9.3 L1-hu3 Ka [1/Ms] 2.6 × 10⁵ 8.0 × 10⁵ Kd [1/s] 2.2 × 10⁻⁵ 6.5 × 10⁻⁵ KD [M] 8.5 × 10⁻¹¹ 8.1 × 10⁻¹¹

Table 2: The humanized variant L1-hu3 displays a similar high target affinity as the parent antibody L1-9.3.

7. Example 7 Antibody Binding to PBMCs and Cancer Cells

PBMC were obtained by density gradient centrifugation from EDTA whole blood of healthy human donors. Cultured OVMZ tumor cells were harvested by trypsination. 1×10⁵ cells/well (75 μl) were seeded into FACS tubes. Dilutions of L1-9.3 mAb were prepared in culture medium with 10 mM EDTA and 75 μl/(well of L1-mAb dilution were added, to PBMCs and OVMZ cells to result in final concentrations between 6.6×10⁻¹³ to 6.6×10⁻⁸ Mol. Subsequently, cells were incubated over night (˜24 h) at 37° C./5% CO2 in an incubator. Cells were washed directly in FACS tubes using 2 ml of FACS buffer followed by centrifugation at 300 g/5 min/4° C. The supernatant was removed by pipetting. For staining, a PE-labelled donkey anti-mouse secondary antibody (Dako) was added at a volume of 150 μl/well followed by incubation for 30 min at 4° C. Washing steps were repeated as above and cells were fixed in 200 μl PBS/1% formaldehyde. Sample mean fluorescence was then measured by FACS analysis.

As shown in FIG. 13, L1-9.3 mAb displays a strongly reduced affinity to L1 on PBMC compared to tumor L1. L1-9.3 binding to PBMC was detected in the nanomolar range (dashed line), while binding to tumor cells could be observed at picomolar concentrations (solid line). B) The dissociation constants K_(D) were estimated from the regression curves using the concentration at half-maximal binding. K_(D) of 11-9.3 on PBMC was at least 400-fold lower than on tumor cells.

8. Example 8 Determination of Cytokine Release

PBMC were obtained by density gradient centrifugation from citrate whole blood of healthy human donors. Cells were resuspended in RPMI 1640/5% human serum/5 ml NEAA/5 ml L-Glutamin/5 ml Natrium-Pyruvat. 1×10⁵ cells per 100 μl were seeded in round bottom 96 well plates. In a second step, 100 μl medium containing LPS (10 ng/ml), L1-9.3 mAb (20 μg/ml), OKT3 mAB (ebioscience) (75 ng/ml) or Ionomycin/PMA (1 μg/ml/5 ng/ml) were added in triplicates followed by an incubation for 24 h at 37° C., 5% CO₂. As negative control, untreated PBMC were used. After 24 h, levels of the cytokines interferone-gamma and tumor necrosis factor were measured by FACS analysis using the CBA-Cytokin-Flex-Sets (BD) according to manufacturers information.

The resulting cytokine levels are depicted in FIG. 14. In contrast to OKT3 mAB, Ionomycin/PMA, and LPS, L1-9.3 did not significantly increase the TNF or IFN-gamma release by PBMCs.

9. Example 9 T-Cell Proliferation Assay

PBMC were obtained by density gradient centrifugation from citrate whole blood of two healthy human donors. 1×10⁵ cells per well were seeded in flat bottom 96 well plates. In a second step, 100 μl medium containing either L1-9.3 mAb (20 μg/ml) and OKT3 (ebioscience, 75 ng/ml) or L1-9.3 mAb (20 μg/ml) or OKT3 (75 ng/ml) was added in triplicates. After 1 h, the latter two were supplemented with OKT3 or L1-9.3, respectively. To exclude any antibody related activation, PBMC with or without L1-9.3 were incubated in absence of OKT3. Following an incubation for 24 h at 37° C., 5% CO₂ T cell proliferation was assessed using a BrdU incorporation assay (Roche) according to manufacturers information.

It can be concluded from the results shown in FIG. 15, that L1-9.3 mAb does neither induce T-cell proliferation or inhibit OKT3 induced T-cell proliferation.

10. Example 10 Glycosylation Dependency of Antibody Binding

2×10⁶ SKOV3ip cells were seeded in a 10 cm petri dish and incubated for 24 h at 37° C., 5% CO₂. After 24 h, cells were washed with PBS and lysed with 500 μl M-PER reagent (Pierce) according to the protocol described in the Seize Classic Mammalian Immunoprecipitation Kit (Pierce). SkOv3ip cell lysate were deglycosylated as described in the Enzymatic CarboRelease Kit (QA_Bio). Briefly, 2.5 μl denaturation solution was added to 35 μl of cell lysate. The sample was incubated in a thermoblock at 100° C. for 5 min and then chilled on ice. Finally 2.5 μl Triton-X and 1 μl of each glycosidase contained in the Enzymatic CarboRelease Kit (QA_Bio) (PGNTase F, O-Glycosidase, Sialidase, β-Galactosidase, Glucoaminidase) were added according to manufacturers protocol followed by an incubation at 37° C. for 3 h. Glycosylated and deglycosylated were subjected to SDS PAGE and subsequent Western blotting. Western blots were incubated with different L1 antibodies in dependence of their staining performance. Concentrations of 1 μg/ml (9.3, 11A and 14.10), 5 μg/ml (35.9) or 10 μg/ml (OV52.24, OV543.18, 38.12, OV549.20) were used. L1 antibody binding to western blot was detected with HRP-labeled anti-mouse antibody (Dianova).

As shown in FIG. 16, the tested anti L1 antibodies can be divided into tree classes in respect to their glycosylation-dependency: First class (unaffected by glycosylation): L1-9.3. Second class (binding in WB was negatively affected by deglycosylation): 11A, 14.10, OV52.24 and OV549.20. Third class (binding in WB was positively affected by deglycosylation): 35.9 and 38.12.

11. Example 11 Biodistribution of L1-9.3 in Rabbit

A female rabbit (White Himalayan) was twice injected with L1-9.3 (0 h, 24 h) via the intravenous application route at a dose of 10 mg/kg. 1 control animal received a comparable volume of PBS. Animals were necropsied 72 h after the first application. Organs were fixed in 4% buffered formalin and embedded in paraffin. Histological slides were prepared and immunohistochemistry was performed. Tissue sections of the L1-9.3-treated and control animal were stained with an anti-mouse antibody to detect binding of L1-9.3 after intravenous application. Signals were visualized by DAB (Sigma). Two different detection systems, conventional Avidin/Biotin Complex method or tyramide signal amplification system CSA II method (Dako) were used, which allowed rough estimation of the amount of in vivo bound L1-9.3. The conventional Avidin/Biotin Complex method (Vector Laboratories) is able to detect L1-9.3 concentrations of 50 ng/ml or higher, while the biotin-free tyramide signal amplification system CSA II (Dako) has a detection limit of 5 ng/ml. To determine the L1 expression pattern, tissues of the control animal were incubated with primary antibody L1-9.3 and with the detection antibody. For ABC method a biotinylated anti-mouse antibody (Dianova, dilution 1:3000) was used as detection antibody, for CSA method was performed according to manufacturers protocol.

FIG. 17 shows the in vivo binding of intravenously applied L1-9.3 to collecting ducts of the kidney. In vivo binding was only detectable using the amplification system CSA (FIG. 17A), while by using the conventional ABC-method, no signal was visible (FIG. 17B). Hence, L1-9.3 was detected in a range of 30-300 pmol in the tissue (L1-9.3 concentration is presumably higher than 5 ng/ml and below 50 ng/ml). Negative control did not show staining, thus, unspecific staining can be excluded (FIG. 17C). The staining pattern of in vivo bound L1-9.3 (FIG. 17A) corresponds to the L1 expression pattern in the kidney when directly staining tissue sections with L1-9.3 (FIG. 17D). It can be concluded that intravenously administered L1-9.3 antibody is able to extravasate to peripheral tissue.

12. Example 12 Function of Humanized Forms of L1 9.3 mAb in Nude Mice

We investigated whether the humanized form of the mAb L1 9.3 could also inhibit the tumor growth of ovarian carcinoma in vivo. First we analysed the binding of the two humanized forms of L1 9.3 to the selected cell line. Therefore, flow cytometry was performed on SKOV3ip pcDNA3.1 Luciferase cells. (FIG. 18). Both mAbs showed strong binding to the tumor cell line, and gave similar binding results as the native L1 9.3 mAb.

SKOV3ip pcDNA3.1 Luciferase cells were injected into immunodeficient mice 24 h before starting the therapy. Humanized antibodies (300 μg) or PBS were injected three times per week intraperitoneally. To detect the tumor growth in vivo, mice were imaged once weekly using the Xenogen JVIS 200 System. Mice were anesthetised and injected with Luciferin D, followed by detecting the light emission which is produced during luciferase activity of the tumor cells. During the time course we detected a slower tumor growth in the group of mice treated with humanized mAb compared to the control. At day 33 the last imaging data were taken. Imaging results gave a decreased tumor volume of around 80% using the hu3 mAb and approximately of 50% for chin 9.3. Both results were strongly significant (FIG. 19). After 36 days mice were sacrificed and tumor mass has determined. In both humanized anti-L1 mAbs treated groups a substantial decreased tumor mass was measured compared to the PBS group (FIG. 20 (A, B)).

13. Example 13

Abolishment of chemoresistance by treatment with anti L1 CAM monoclonal antibody 9.3 was tested as described in WO 2008/046529, Example 3 (see also FIG. 17 e of WO 2008/046529). The results are shown in FIGS. 21 and 22. It could be demonstrated that the monoclonal antibody 9.3 abolishes chemoresistance. Its effect seems to be stronger than those of the antibody 11A tested in WO 2008/046529.

TABLE 1 Western mAb FACS blot IP L1-Fc Invasion phospho-Erk ka (1/Ms) kd (1/s) KD (M) tumor growth L1-9.3 +++ +++ +++ +++ −60% −50% 2.6E+05 2.2E−05 8.5E−11 −60% L1-11A +++ +++ +++ +++ −50% −40% 1.0E+05 4.0E−06 4.0E−11 −40% L1-14.10 + ++ + +++ −40% −40% 1.4E+04 1.0E−06 7.1E−11 −30% L1-38.12 + +++ + +++ 0 0 3.7E+04 2.0E−06 5.4E−11 L1-35.9 + +++ + +++ 0 0 4.0E+04 1.2E−05 3.0E−10 L1-N15.17 ++ − ++ ++ 0 0 5.3E+04 1.0E−03 1.9E−08 L1-1D12.22 − − + ++ 0 −20% 2.3E+04 1.0E−04 4.3E−09 L1-1D17.3 − − + ++ 0 0 2.3E+04 1.0E−04 4.3E−09 L1-1D64.8 − +++ + +++ 0 0 8.5E+04 1.5E−04 1.8E−09 L1-1D74.8 − +++ + +++ −10% 0 3.0E+04 2.0E−03 6.7E−08 

The invention claimed is:
 1. A purified anti-L1CAM monoclonal antibody which is capable of binding to the same L1CAM epitope recognized by the monoclonal antibody 9.3, produced by the hybridoma cell deposited under DSMZ ACC2841.
 2. The purified anti-L1CAM monoclonal antibody of claim 1, having the same capacity to inhibit tumor growth as the monoclonal antibody 9.3, produced by the hybridoma cell deposited under DSMZ ACC2841.
 3. A purified anti-L1CAM monoclonal antibody, wherein its six complementarity determining regions (CDRs) comprise the following sequences: RASQDISNYLN (SEQ ID NO: 1), YTSRLHS (SEQ ID NO: 2), QQGNTLPWT (SEQ ID NO: 3), RYWML (SEQ ID NO: 4), EINPRNDRTNYNEKFKT (SEQ ID NO: 5), and GGGYAMDY (SEQ ID NO: 6).
 4. A purified monoclonal antibody, produced by the hybridoma cell deposited under DSMZ ACC2841.
 5. The purified anti-L1CAM monoclonal antibody of claim 3, wherein the antibody is a humanized antibody.
 6. The purified anti-L1CAM monoclonal antibody of claim 3, wherein the antibody is a humanized antibody and comprises non-human CDR and human framework region (FR) residues.
 7. The purified anti-L1CAM monoclonal antibody of claim 3, wherein the antibody is a humanized antibody comprising (i) a sequence comprising SEQ ID NOs: 20 and SEQ ID NO: 24; or (ii) a sequence comprising SEQ ID NOs: 21 and
 25. 8. A purified antibody or antigen-binding fragment thereof comprising the following sequences: RASQDISNYLN (SEQ ID NO: 1), YTSRLHS (SEQ ID NO: 2), QQGNTLPWT (SEQ ID NO: 3), RYWML (SEQ ID NO: 4), EINPRNDRTNYNEKFKT (SEQ ID NO: 5), and GGGYAMDY (SEQ ID NO: 6).
 9. The antibody or fragment of claim 8, wherein the antibody or fragment is selected from the group consisting of single chain antibodies (scFv), multimers of scFv, diabodies, triabodies or tetrabodies, Fab, tandabs, flexibodies, bispecific antibodies, chimeric immunoglobulins and humanized immunoglobulins.
 10. The purified anti-L1CAM monoclonal antibody of claim 3, wherein the antibody is linked to an active substance selected from the group consisting of a toxin, a cytokine, a nanoparticle and a radionuclide.
 11. The hybridoma cell deposited under DSMZ ACC2841.
 12. A pharmaceutical composition comprising the purified anti-L1CAM monoclonal antibody of claim
 3. 13. The antibody or fragment of claim 8, wherein the antibody or fragment is linked to an active substance selected from the group consisting of a toxin, a cytokine, a nanoparticle and a radionuclide.
 14. The purified anti-L1 CAM monoclonal antibody of claim 1, wherein the antibody is a humanized antibody.
 15. The purified anti-L1CAM monoclonal antibody of claim 1, wherein the antibody comprises six complementarity determining regions (CDRs) that comprise the following sequences: RASQDISNYLN (SEQ ID NO: 1), YTSRLHS (SEQ ID NO: 2), QQGNTLPWT (SEQ ID NO: 3), RYWML (SEQ ID NO: 4), EINPRNDRTNYNEKFKT (SEQ ID NO: 5), and GGGYAMDY (SEQ ID NO: 6). 